1. Field of Invention
The present invention relates to a wall structure working as a noise barrier for railways and use of the wall structure as a noise barrier and/or passage barrier.
2. Description of Related Art
The solution according to the invention is particularly suitable as e.g. a shallow noise barrier for railways, but it is also suitable as a noise barrier for highways and also as a sight barrier for various applications. Owing to its lightness, it can also be used as a temporary barrier for many different applications.
European patent application no. EP1172484 A2 presents one general wall structure constructed on a prior-art principle and working as a noise barrier. It contains a plurality of solid foundation elements, which are manufactured from e.g. concrete, in the direction of the barrier. The foundation elements are disposed in a line consecutively for the length of the fence to be constructed and plate-like elements, which together with the foundation elements form a noise barrier, are fixed onto the top edge of the foundation elements between vertical pillars. In, for example, railway use one concrete foundation element of a corresponding type will weigh thousands of kilograms, so that it is difficult to place into position, and after placing into position it is difficult to move, and moving will succeed only with large machines that might have difficulties gaining access to all the necessary points of a track area. If a noise barrier thus constructed must for some reason, e.g. for overwide carryings or owing to an accident, be quickly removed, this will not always succeed because a large machine for moving a heavy foundation element will not necessarily be immediately available.
Also known in the art are wall structures that work as a noise barrier, in which the part functioning as a noise barrier is disposed between vertical pillars fixed directly into the ground. A problem in these structures is temporary disassembly of the noise barrier when there is, for various reasons, a need for it. Although the section between the pillars could be disassembled easily, the pillars are generally firmly fixed in the soil and, e.g. owing to ground frost, sunk deep into the ground. For this reason it is not easy to take a pillar out quickly, and it might be necessary in an emergency to cut the pillars in order to get them out of the way. In this case re-erecting the barrier is slow and expensive.
A drawback in railway use is that, with the noise barriers that are currently known in the art, any work to service the track at the point of the noise barrier is dangerous because it is not generally worth disassembling the noise barrier during the servicing work, or is it generally feasible. In this case the track section in question must be completely closed to train traffic for safety reasons during the servicing work, which also incurs extra costs.